title: A Rasch-validated version of the upper extremity functional index for interval-level measurement of upper extremity function.
abstract: BACKGROUND
  The original 20-item Upper Extremity Functional Index (UEFI) has not undergone Rasch validation.
  
  
  OBJECTIVE
  The purpose of this study was to determine whether Rasch analysis supports the UEFI as a measure of a single construct (ie, upper extremity function) and whether a Rasch-validated UEFI has adequate reproducibility for individual-level patient evaluation.
  
  
  METHODS
  This was a secondary analysis of data from a repeated-measures study designed to evaluate the measurement properties of the UEFI over a 3-week period.
  
  
  METHODS
  Patients (n=239) with musculoskeletal upper extremity disorders were recruited from 17 physical therapy clinics across 4 Canadian provinces. Rasch analysis of the UEFI measurement properties was performed. If the UEFI did not fit the Rasch model, misfitting patients were deleted, items with poor response structure were corrected, and misfitting items and redundant items were deleted. The impact of differential item functioning on the ability estimate of patients was investigated.
  
  
  RESULTS
  A 15-item modified UEFI was derived to achieve fit to the Rasch model where the total score was supported as a measure of upper extremity function only. The resultant UEFI-15 interval-level scale (0-100, worst to best state) demonstrated excellent internal consistency (person separation index=0.94) and test-retest reliability (intraclass correlation coefficient [2,1]=.95). The minimal detectable change at the 90% confidence interval was 8.1.
  
  
  CONCLUSIONS
  Patients who were ambidextrous or bilaterally affected were excluded to allow for the analysis of differential item functioning due to limb involvement and arm dominance.
  
  
  CONCLUSIONS
  Rasch analysis did not support the validity of the 20-item UEFI. However, the UEFI-15 was a valid and reliable interval-level measure of a single dimension: upper extremity function. Rasch analysis supports using the UEFI-15 in physical therapist practice to quantify upper extremity function in patients with musculoskeletal disorders of the upper extremity.
authors.affiliation: C.B. Hamilton, MSc, Graduate Program in Health and Rehabilitation Sciences and Collaborative Graduate Program in Musculoskeletal Health Research, Western University, Room 1011, Elborn College, 1201 Western Rd, London, Ontario, Canada N6G 1H1.
authors.forename: Clayon B
authors.initials: CB
authors.lastname: Hamilton
authors.forename: Bert M
authors.initials: BM
authors.lastname: Chesworth
mesh_terms: D000203:Activities of Daily Living; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002170:Canada; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009140:Musculoskeletal Diseases / Q000503:physiopathology*; D011594:Psychometrics / Q000379:methods*; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D034941:Upper Extremity / Q000503:physiopathology*; D055815:Young Adult